Advanced JSON Validator

Validate JSON against custom schemas with instant error reporting and exact field matching. 100% client-side.

Exact fields only (no extra fields allowed)
Generate Schema from JSON
ℹ️ Enter your source JSON to begin
Schema Configuration
Enter valid JSON in the source panel to configure field validation rules
JSON to Validate
⏳ Waiting for validation

How to Use the JSON Validator

1

Prepare Your JSON Data

Paste your sample JSON in the "Generate Schema from JSON" panel. This will be used to automatically create a validation schema.

{
  "name": "John Doe",
  "age": 30,
  "email": "john@example.com",
  "active": true
}
2

Configure Validation Rules

Use the Schema Configuration panel to set field requirements, data types, and format validations. Click on each field to expand and customize validation rules.

  • Set fields as required or optional
  • Choose appropriate data types (string, number, boolean, etc.)
  • Add format validation for emails, URLs, dates, etc.
  • Enable "Exact fields only" to prevent extra fields not defined in your schema
3

Validate Your JSON

Paste or import the JSON you want to validate in the "JSON to Validate" panel and click "Validate JSON". The tool will check your data against the configured schema and report any errors.

4

Export and Import Schemas

Save your validation schemas for reuse by exporting them as JSON files. Import previously saved schemas to quickly set up validation for similar data structures.

Use Case Examples

API Response Validation

Validate JSON responses from REST APIs to ensure they match expected schemas before processing in your application.

Schema: 
{
  "userId": "string (required)",
  "email": "string (email format)",
  "createdAt": "string (ISO datetime)"
}

Configuration File Validation

Ensure configuration files follow the correct structure and contain all required settings before deployment.

Example: 
{
  "database": {
    "host": "string (required)",
    "port": "number (1000-9999)",
    "ssl": "boolean"
  }
}

Data Import Validation

Validate JSON data before importing into databases or processing pipelines to prevent data corruption.

Validation Rules: 
{
  "products": "array (min 1 item)",
  "total": "number (positive)",
  "currency": "string (USD|EUR|GBP)"
}

Strict Schema Enforcement

Ensure your JSON data exactly matches the defined schema by enabling exact field validation. Perfect for APIs that require strict adherence to specifications and prevent unexpected data.

Configuration: 
{
  "exactFieldsOnly": true,
  "message": "No extra fields allowed"
}

Frequently Asked Questions

How does the JSON Validator work?

Our validator analyzes your JSON structure and validates it against custom schemas you define. It provides instant error reporting and supports advanced features like required fields, data types, and format validation.

What is JSON Schema validation?

JSON Schema is a vocabulary that allows you to annotate and validate JSON documents. Our tool helps you create and apply schemas to ensure your JSON data meets specific requirements and structure.

Is my data secure?

Yes! All validation happens client-side in your browser. Your JSON data never leaves your device or gets transmitted to our servers, ensuring complete privacy and security.

What validation rules are supported?

We support comprehensive validation including data types (string, number, boolean, array, object), required fields, string formats (email, URL, regex), number ranges, and array constraints.

Related Tools

After validating your JSON, try our JSON Merge Tool to combine multiple JSON objects, or use the CSV ↔ JSON Converter to convert between CSV and JSON formats.

What is the "Exact fields only" feature?

This feature ensures that your JSON data contains only the fields defined in your schema. When enabled, any extra fields not specified in the schema will be flagged as validation errors, helping maintain strict data structure compliance and prevent unexpected data from being accepted.